Removal all idle-task implementations in toBlob

third_party/WebKit/LayoutTests/fast/canvas/canvas-toBlob-defaultpng.html

-<script src = "../../../resources/js-test.js"></script>
+<script src = "../../resources/js-test.js"></script>
 <script type = 'text/javascript'>
 jsTestIsAsync = true;
 description("Test that verifies whether the image data survives the toBlob process after async image encoding");
 
 if (window.testRunner) {
+    testRunner.dumpAsText();
     testRunner.waitUntilDone();
 }
 
 var canvas = document.createElement("canvas");
 var ctx = canvas.getContext("2d");
 ctx.fillStyle = "#FF0000";
 ctx.fillRect(0, 0, 150, 75);
 var canvas2 = document.createElement("canvas");
 var ctx2 = canvas2.getContext("2d");
 
@@ skipping 20 matching lines @@
 
     finishJSTest();
 }
 
 canvas.toBlob(function(blob) {
     url = URL.createObjectURL(blob);
     newImg.src = url;
 });
 
 </script>